Conveyor belts are used in a variety of industries (e.g., coal, aggregate, packaging) to transport goods and materials. Based on the material transported and the ambient conditions surrounding the conveyor belt, material can become undesirably affixed to the belt. The material can be removed from the belt in a number of ways, including, but not limited to the use of a belt cleaning apparatus utilizing spring tensioners.
A belt cleaning apparatus cleans the belt in place, during operation, via a scraping action thereagainst. A belt cleaning apparatus typically will include a cleaner blade or blades having a scraper or tip end that is biased into engagement with the belt surface, usually on the return run of the belt (secondary belt cleaners) or at the head pulley (primary belt cleaners). In either type of belt cleaner, the scraper blade will typically be mounted to an elongate pole extending below and across the belt to the frame structure of the conveyor system on either side of the belt for being operatively supported thereby. In this regard, the opposite ends of the pole can be mounted to biasing units secured to frame structures for providing an upward bias force for urging the scraper blade into engagement with the belt surface.
Exemplary prior art spring tensioner units are disclosed in U.S. Pat. Nos. 6,874,616 to DeVries and 7,093,706 to DeVries, which are incorporated as if reproduced in their entirety herein. These units provide both a rotary bias force and an upward, linear bias force to the pole via a Rosta-type torsion biasing mechanism and a spring loaded housing assembly of the torsion biasing mechanism. Depending on space requirements, the tensioner units are mounted to the conveyor frame structure with either a pull-up or push-up configuration. In the pull-up configuration the coil spring providing the linear bias force is arranged on the fixed mounting frame flange above the housing assembly mounted for translation along the mounting frame member to exert an upward bias force that draws or pulls the housing assembly upward. In the push-up configuration the tensioner unit is rotated 180 degrees about the longitudinal axis of the mounting pole. In this configuration, the coil spring is arranged below the housing assembly and between the fixed mounting frame flange and the translatable housing assembly to exert an upward bias force that pushes the housing assembly upward. However, switching from one configuration to another requires significant disassembly and re-assembly of the unit.
More particularly, the coil spring has to be reoriented relative to the mounting frame flange of the unit against which the spring abuts. To do this, the entire housing assembly is detached from the guide bearings on the mounting bracket. This allows the position of the spring to be changed from one side of the bracket flange to the other with the housing assembly then reconnected to the linear guides on the bracket once the spring is properly positioned. The disassembly required for reconfiguring the tensioner units is undesirable from a time and labor standpoint.
Accordingly, there is a need for a spring tensioner that can be more easily reconfigured between pull-up and push-up configurations.